In connection with the defibration and refining of cellulose-containing material so-called refiners are utilized, and they are often of the disc refiner type. These types of refiners are employed for the refining of cellulose and mechanical pulps of different kinds, particularly when it is desired to develop the paper forming properties of these materials by mechanical processing. All such defibration and refining includes the common characteristics that the desired results are achieved by processing the fibrous material while it is passing through the refiner. Such processing is achieved by the fibrous material, after having been fed into the refiner by various devices, passing out of the refiner through a narrow gap between two refining surfaces, which for this purpose are provided with refining members in the form of bars and intermediate grooves. Owing to the rotation of one and, at times, both said surfaces, the material is refined in the desired manner, and then transported out of the refiner by rotational forces. Specifically, U.S. Pat. No. 2,156,321 discloses a fibrous pulp refiner which specifies a particular width and depth for the grooves on the refining surface of the refining members (i.e., the refiner disc segments).
The intensity and nature of the processing of the fibrous materials are determined, for example, by the existence and number of bars and grooves which appear on the refining surfaces, and by the size of the gap between these surfaces. As a certain amount of wear of the refiner discs cannot be avoided, disc refiners are generally equipped with exchangeable refining members, or so-called refiner disc segments. These refiner disc segments are provided during their manufacture with a pattern and profile in accordance with the work to be carried out in the refiner. The energy required for defibration and refining is thus transferred to the fibrous material via the edges and surfaces of the bars.
It can therefore be stated that the design of the bars and grooves on these refiner disc segments is of importance for the energy consumption during the refining of cellulose material, especially at high concentrations, e.g., above about 20%. Even apparently small variations in the pattern of the refiner disc segments can thus cause considerable variations in the energy consumption therewith.
It is a shortcoming of the prior art that it does not disclose any relationship between the width of the bars and the width and depth of the grooves and the energy consumption of the refining process. In particular, specific prior art reference may only disclose a particular width and depth for the bars and grooves, but they do not teach any relationship between the width of the bars, the width and depth of the grooves, and the energy consumption of the refining process.